The following cost graphs illustrate various types of cost behavior:

For each of the following costs, identify the cost graph that best illustrates its cost behavior as the number of units produced increases.
a. Total direct materials cost
b. Salary of quality control supervisor, $4,000 per month
c. Electricity costs of $2,000 per month plus $0.02 per kilowatt-hour
d. Per-unit direct labor cost
e. Per-unit cost of straight-line depreciation on factoryequipment

Cost Graph One Cost Graph Two 0 Total Units Produced 0 Total Units Produced Cost Graph Three Cost Graph Four 0 Total Units Produced 0 Total Units Produced